Which variant of Portuguese is mainly used on Portuguese Wikipedia - European or Brazilian?
According to Wikipedia, because of the number of edits, it's mainly Brazilian, but you can write also in European.
It's recommended that it be left as is when the edit of the article is about the flavor. But I guess Brazilian people edit even with this recommendation.
Historically many requests to open exclusive European or Brazilian wikis were rejected.
Both, they are basically the same in written form, just like you see in Wikipedia in English, is it more British or more American? When something is different, it is differed like that:
(entry for "hydrogen")
O hidrogénio (pt-PT) ou hidrogênio (pt-BR)...
Just like English:
(entry for "colour")
Color (American English), or colour (Commonwealth English)...